The present invention relates to a film material for manufacturing film carriers and its manufacturing method, and more particularly, to a film material which becomes a material in manufacturing the film carriers for mounting semiconductor chips, and a method of manufacturing the film material.
There is known a film carrier system referred to as the package construction of semiconductor chips such as IC, LSI and so on. This is produced by a method comprising the steps of forming a conductive metallic layer of Cu foil or the like on the film tape, effecting an etching operation on the conductive metallic layer to form lead patterns for manufacturing the film carriers, punching, separating the film carriers for each of the individual lead patterns after bonding the semiconductor chips to the lead patterns on the film carriers, and obtaining the film carrier chips with the semiconductor chips mounted being thereon.
FIG. 6 and FIG. 7 show the construction of representative known film carrier chips. FIG. 6 shows a bonding wire type of film carrier chip with the connection between the semiconductor chip and the lead pattern of the film carrier being effected with bonding wires. The lead pattern 20 composed of conductive metallic layer of Cu or the like is formed in the given pattern shape on the film 10 made of polyimide resin or the like. After the the semiconductor chip 30 has been fixedly mounted by the means of soldering, bonding or the like on the film 10, the respective electrodes and the lead pattern 20 are electrically connected with the bonding wires 40. The periphery of the semiconductor chip 30 is covered with the sealing resin 50.
FIG. 7 shows a bump type of film carrier chip which effects with bumps the connection of the semiconductor chip and the lead pattern of the film carrier. The point of difference between FIG. 6 and FIG. 7 is that the lead pattern 20 extends as far as each electrode position on the reverse face of the semiconductor chip 30, the lead patterns 20 and the respective electrodes are electrically connected with each other through the bumps 70 made of Au, solder or the like on the extended lead pattern 20 and the semiconductor chip 30 itself is secured onto the film 10.
In the case of the wire bonding type, it is inconvenient to connect the respective electrodes of the semiconductor chip 30 respectively with the lead pattern 20 by bonding wires 40 and also, sufficient intervals among the electrodes are required to effect the wire bonding operation, with a problem that the whole plane size of the electrode intervals and the semiconductor chip 30 become larger. Also, as the bonding wires 40 are projected from the surfaces of the semiconductor chip 30, the external shape of the sealing resin 50 becomes larger to completely cover the whole of the bonding wires 40, with the defect that the height of the whole film carrier chip becomes larger.
On the other hand, in the case of the bump type, effect the heating and pressing operations are collectively effected with the bump 70 being grasped between the electrodes of the semiconductor chip 30 and the lead patterns 20, and all the connections may be effected at one time and the connecting operation may be extremely efficient. As the connection may be effected if the intervals among the electrodes are narrower, the area of the electrode intervals, namely, the semiconductor chip 30 may be made smaller. The bump 70 is hidden on the reverse face of the semiconductor chip 30, and also, is slight in thickness, so that the bump becomes thinner even in the thickness direction. As a result, the size of the whole film carrier chip may be made smaller.
As the bump type is superior to the wire bonding type for the above described reasons, it is used for smaller types of packages.
But the bump type of film carrier chip had a disadvantage in that no flexibility was provided with respect to the electrode layout of the semiconductor chip 30.
Namely, the outer lead portion 21 for the connection to the external circuit of wiring basic plate or the like among the lead patterns 20 of the film carrier chip may be used as it is into the various mounted forms if it is kept set to the constant standard size. As the electrode layout of the semiconductor chip 30 is completely different depending upon the construction of the individual semiconductor chip 30, the inner lead portion 22 of the lead pattern 20 has to be formed in accordance with the electrode layout of the semiconductor chip 30, namely, the layout of the bump 70.
Therefore, in the film 10 provided with the lead pattern 20 having a constant pattern of inner lead portion 22, namely, the film carrier, the film carrier provided with the lead pattern 20 different in the forming pattern had to be manufactured each time the electrode layout of the semiconductor chip 30 changes, because it cannot be used for the mounting use of the semiconductor chip 30 different in the electrode layout. When the forming pattern of the lead pattern 20 changes, the mask or model for etching use has to be prepared for each of the respective patterns, with problems that the apparatus cost is increased, the plan for the apparatus has to be changed for each of the pattern changes, and more operation time is required.
Especially in recent years, the number of the electrodes of the semiconductor chip has increased, and also, more product types and lower production runs are present which presents extremely important problems in that the long hours or lead time of manufacturing the mask for etching use, or the like is set each time the product type changes and the initial cost increases.